Influence of the calcination method and anode composition on the generation of disinfectants

Abstract

Developing highly selectivity anode materials for hypochlorite generation in low-concentrated sodium chloride (NaCl) solutions is challenging. Here, we describe the synthesis and physical and electrochemical characterization of ruthenium-based binary anodes (Ti/RuO2 − Sb2O4 and Ti/RuO2 − TiO2) prepared by different heating methods (laser, microwave, and furnace). The heating method and chemical composition were crucial in the anode characteristics and catalytic activity. The anodes of Ti/RuO2 − Sb2O4 composition prepared by laser and microwave show an increase in voltammetric charge by 1.4 and 1.9-folds and a decrease in resistance to charge transfer by approximately 2-folds compared with the corresponding furnace-made anode. The Ti/RuO2 − TiO2 anode prepared by unconventional methods (laser and microwave) shows an increased voltammetric charge in approximately 3-folds and reduced resistance to charge transfer at 5.6 and 3.4 times, respectively, compared with the anode prepared in an electric furnace. The composition of MMO and the applied current density are the main factors that influence the production of ClO and chloramine disinfectants. The highest electrocatalytic activity for generating hypochlorite from low-concentrated NaCl solutions was obtained by the Ti/RuO2 − TiO2 anode prepared by laser heating using a current density of 60 mA cm−2. Additionally, we evaluated the electrochemical generation of inorganic chloramines. Consequently, this study offers new insights into the preparation of low-cost materials for efficient in situ generation of disinfectants.